The guys at Opal Sock Yarn sent me quite a bit of what they had left from their first US shipment of the Harry Potter sock yarn. I do have a lot of it (several large boxes arrived yesterday afternoon), but I do think that it will sell out by later tonight. You can find it here, and those of you that pre-ordered the entire collection in the past two weeks will see your yarn arrive soon.
When you see the yarn disappear from the website, that means it's sold out. But I do expect even more to arrive in about 3 weeks from the second US shipment.